1. Field of the Invention
This invention relates to novel copolymers and is more particularly concerned with novel copolymers of acrylates and with methods for their preparation and their use as carbodiimide catalysts.
2. Description of the Prior Art
It is known that certain phospholene oxides are catalysts for the conversion of isocyanates to carbodiimides; see U.S. Pat. No. 2,853,473. It has also recently been disclosed (see German Offenlegenschrift No. 2,504,334; published after the present invention was made) that certain phospholene-phosphonic acid salts of amino-modified polystyrenes can be employed as catalysts for the same reaction.
We have now found that certain copolymers of alkyl acrylates and the di-acrylates of 1-dialkanolaminophospholene-1-oxides are highly effective catalysts for the conversion of organic isocyanates to the corresponding carbodiimides and are possessed of marked advantages when employed for this purpose.